12-1: Spinal Cord - structure

Question 1

The spinal cord is a cylinder of __NS tissue continuous with the ___.

Answer 1

CNS tissue; medulla of the brainstem

Question 2

The spinal cord begins at __ and ends __.

Answer 2

foramen magnum; between vertebrae L1 & L2

Question 3

What are the visible enlargments in the cord?

Answer 3

cervical enlargement - nerves that supply the arms come from this region

lumbar enlargement - nerves that supply the legs come from this region

Question 4

conus medullaris

Answer 4

tapered end of spinal cord below lumbar enlargement

Question 5

cauda equina

Answer 5

collection of spinal nerves fanning out from inferior end of cord

Question 6

What is a bundle of axons in the PNS called?

Answer 6

nerve

Question 7

What is a bundle of axons in the CNS called?

Answer 7

tract

Question 8

What are the types of tracts in the CNS?

Answer 8

ascending tract - made of sensory neurons carrying sensory impulses UP the cord to the brain

descending tract - made of motor neurons carrying motor impulses DOWN the cord

Question 9

What is a cluster of neuron cell bodies in the PNS called?

Answer 9

ganglion

Question 10

What is a cluster of neuron cell bodies in the CNS called?

Answer 10

nucleus

Question 11

What grooves divide the spinal cord into right and left halves?

Answer 11

posterior median sulcus and anterior median fissure

Question 12

A region of grey matter is called __.

Answer 12

horn

Question 13

Gray matter consists of:

Answer 13

cell bodies, unmyelinated axons and neuroglia; forms an H shaped area in the center of the cord

Question 14

anterior/ventral horn

Answer 14

cell bodies of outgoing somatic motor neurons

Question 15

posterior/dorsal horn

Answer 15

cell bodies of incoming sensory neurons and interneurons

Question 16

lateral horns

Answer 16

cell bodies of autonomic neurons

Question 17

Sensory signals come from the __ of the cord and motor signals come from the __.

Answer 17

back; front

Question 18

gray commisure

Answer 18

crossbar of the H - encloses the central canal

Question 19

central canal

Answer 19

runs the length of the cord and is filled with cerebrospinal fluid; enclosed in the gray commisure

Question 20

white matter

Answer 20

groups of myelinated axons forming ascending and descending tracts outside the gray matter.

Question 21

White matter forms areas called:

Answer 21

columns

Question 22

What are the three columns of white matter?

Answer 22

posterior (dorsal) columns; anterior (ventral) columns; lateral columns

consist of ascending and descending tracts named from their origin and destination (eg. anterior spinothalamic tract - origin is spine and destination is thalamus)

Question 23

The spinal cord is enclosed in ___ formed by ___.

Answer 23

the spinal canal; formed by the vertebral foramina of the vertebrae stacked on top of each other

Question 24

cerebrospinal fluid

Answer 24

clear fluid that circulates in the subarachnoid space around the cord and cushions it from shock

Question 25

meninges

Answer 25

connective tissue covering around the brain and spina l cord

Question 26

What are the spinal meninges (superficial to deep)?

Answer 26

``` [bone] >epidural space 1. dura mater 2. arachnoid >subarachnoid space 3. pia mater ```

Question 27

dura mater

Answer 27

most superficial meninge; outer layer of dense connective tissue, forms tube around cord called spinal dural sheath

Question 28

epidural space

Answer 28

between dura mater and bone; filled with fat and blood vessels, and provides soft padding around the cord

Question 29

arachnoid

Answer 29

fine, spiderweb-like connective tissue between the dura mater and the pia mater

Question 30

subarachnoid space

Answer 30

between arachnoid and pia mater; where CSF circulates

Question 31

pia mater

Answer 31

deepest meninge; delicate, transparent membrane on surface of spinal cord

Question 32

meningitis

Answer 32

an inflammation of the meninges (bacterial or viral)

Question 33

Anestetics are injected into ___ and lumbar punctures are done ____.

Answer 33

epidural space; subarachnoid space